Telephone repeater system.



H. E. SHRBEVE. TELEPHONE RBPEATER SYSTEM. APPLICATION FILED IEB.24, 1912.

Patented Sept. 30, 1913.

Imm.

NN n HERBERT E. SHREEVE, F MILBURN, COMPANY, 0F NEWf YORK,

NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC N. Y., A CORPORATION OF ILLINOIS.

TELEPHONE REPEATER SYSTEM.

Specification of Letters Patent.l i Application led February 24, 1912. Serial No.

Patented Sept. 30, 1913. 679,558. p

. To all whom z'f may concern:

circuit.

Be it known that I, HERBERT E; SHREEVE, subject of the King of England, residing at Milburn, in the county of Essexand State` of New Jersey, have invented a certain new and useful Improvement in Telephone Repeater bystems,y of which the following is a full. clear, concise, and eXact description.

This invention relates to telephone relay or'repeating systems, and more particularly to a system in which Athe repeating apparatus, including its local repeating circuit, is associated with the two'ends of a link circuit in such manner that when the link circuit is connected with the ina-in circuits it constitutes a connection between the tw-o main circuits uniting them into a single compound circuit for through communication.

vOne of the objects of this invention is to provide means for connecting Aa telephone receiver to the repeater circuit in such a manner that it will provide an adequate volume of receiving for supervisory purposes and'Wil'l not appreciably shunt transmission and will not unbalance the repeater This is accomplished by providing a supervisory coil having one receiver windingin inductive relation to a plurality of line windings connected on both sides of the circuit so that any differences in phase of the variation on opposite sides of the repeater will be readily indicated and reactive line disturbances will be obviated..

Another object of this invention is to provide an eiiicient means for regulating or adjusting the repeaterto operate on particular line combinations and to compensate for -certain variables such as a fluctuating battery voltage due to charge and discharge and high resistance of-the transmitter element in the repeater itself due to continuous use. This is accomplished by changing the phase relation of the input and output current ef the repeater-to the conditions of unbalance met with and regulating the output of the transmitting element toy the same conditions. The means for accomplishing this consists in placingla variable resistance iny series with the magnetizing winding and i line.

rents to the conditions of unbalance of the line.

,Another feature of this invention relates to the means provided for preventing the humming of the repeater in case one end of the link is accidentally disconnected from thel This feature consists in providing a relay in the third Wire circuit or sleeve strand of the connectors, one of these relays being adapted whenoperated to put battery on the repeater, close the secondary coil which supplies current to the receiving element.

Another feature of this invention relates to the connection vof the supervisory relay whereby the balance of the system is maintained. This consists in bridging.' the supervisory relay at the center of the system in shunt of the repeater bridge. This accomplishes two things :-First, it renders the system balanced and it provides a system in which the supervisory relay is equally sensitive to ringing currents from each side.

The drawing is a circuit diagram of the apparatus ,illustrating all of the features of this invention 4in connection with a cord circuit.

Referring to the drawing, 5 and 6 desig' nate three conductor plugs located one at each end of the repeater cord circuit and adapted .for insertion into jacks (not shown) of the lonfr dist-ance lines terminating in the same office 4as the repeater cord circuit. Connected in the tip and ring conductors 7 and 8 of the plugs 5 and l6, are secondary windings induction coil, the primal" 12 of Which is connected Witha sourceo current and the transmitter element of a repeater 15. The repeater l5 is preferably of the type shown and described in UDS. Letters Patent No. 836,612 issued tome November 20th, 1906,

the'other being adapted t0 Y or my co-pending application .Serial No. May 25, 1911; and comprises a transmitter element 16, a receiver or operating winding 17 andv a magnetizing winding 18.l 'Connected with the. middle point of the windings 10, and in series with a condenser 19, is a primary winding 2O of an induction coil 21, the secondary 22 of which is adapted for connection with the o erating winding 17 of the repeater .t rou h contacts on a relay 23. Also connecte with the middle point of thewinding 11 in shunt with the repeater bridge and in series with a retardation coil 24, and a condenser 25, is a supervisory 'relay 26, the contact of which controls a, slow-acting relay 271 which, when operated, locks up and completes a circuit for a supervisory lamp 28. The relay 27 is made sluggish in its opv eration by means of a copper sleeve or collar 29 for the purpose of preventing this relay operating upon discontinuous or momentar impulses of current such as result facessi, sied from t e operation of telegraph apparatus connected with the line.

Connected in the sleeve strand 3Q of the plug 5 is a relay 31 the plug 5 is inserted into the jackof the desired line, and, when o erated, closes contacts in the repeater bri ge. strand 32 of the plug 6 is a relay 33 operated upon the insertion of itsjack. y The relay 33 is adapted w en operated to connect battery 34 with the transmitter element 16 of the repeater 15; also with relays 35 and .36, the relay 35 being adapted when operated to complete the repeater bridge, and the relay 36 ing adapted to open a short circuit of thewindings 10 and 11 normally maintained through the back contacts of said relay. In circuit with the battery 34 is a special switching key such as shown and vdescribed in my allowed application Serial No. 654,279, tiled October 12, 1911. This key comprises in general four'sets of contact springs 40, 40v of' the same length, and one set of springs 41 shorterthan the springs 40, 40, together with a longitudinall -movable reciprocating plunger 42, adapte iii one position to be f moved into engagement with the longer contact springs only, and in its other position to engage all of the contact springs. The operation of the longer contact springs40, 40 completes a circuit from the battery 34 through resistance 43, 43 and the operation of the springs 41 completes a circuit for the pole changing relay 23.

Connected in the tip and ring conductors of thev cord on each side of the windings 10 and 11 are primary windings 50, 50 and 5l, 51 of a repeatin coil, the secondary'52 of which is adapte tobe connected with the operators receiver 53 through a key 54.

-receiving which results.

which is operated whenA In the sleeve the plu ,6 into i With' this arrangement ofwindings on both 65 sides of the repeater, any diierences in phase in the currents onfopposte sides of the repeater will be readily detected in the blurred `One pair of the windings 50,51 is connectedwith one "side 'of a cut-ofi key 55, the other pair of said windings being connected with the other side of said key, enabling the op in either direction without interference from the thirdv party. l

The telephone receiver 53 forms part of an o erators telephone set, comprising in addition a transmitter 58, lo'calbattery 59, and primary 60 of ansecondary 61 of which comprises twolwindings, one of which is ada ted to be connecterator to talk on to theline induction coil, the

the operation' of this key ed in series with the receiver, and in bridge j of the tip and' ring by means of a talk and listen key 62. The magnetizing winding 18 of the repeater is connected to ground through a retardation coil 65, and this coil 65, and winding 18 are shunted b a condenser 66; the function of the retar ation coil 65 is to limit the ow of current through the winding 18, and that of the condenser 66 to localize the microphone currents in the transmitter button and primary winding and to exclude such currents from the magnetizing winding 18.

Referring now to the operation of the apparatus and circuits, it will be assumed that .the plugs 5 and 6 are inserted into the jacks (not shown) .of the lines which are to talk through the repeater; with these plugs'inserted, ground will be connected with the sleeve contacts thereof and circuits completed for the sleeve relays 31 and 33. The operation of the relay 31 closes its front contacts 80 and 81, andthe operation of the relay 33 closes its contacts 82 and 83. The closing of these contacts is preliminary to the succeeding operation which is the movement of the key slide 42 into position to close the first air of contacts 40. The closure of this pair of contacts completes two paths for current, one of which may be traced from the battery 34 through the contacts 82 and 83 of relay 33, conductor 84, contacts 40, resistance coils '43, 43, conductor 85, winding 12 of the induction coil of the repeater, conductor 86 to one electrode of the transmitter16 of the repeater, through lthe comminuted material' to' the other electrode thereofconductor 87, conductor 88, magnetizing winding 18 of the repeater. and retardation coil 65 to ground. Theoth conductors of the cord' and 83 of relay 133', conductor 84, contacts 40, conductor90'winding of relay 35, conductor 91 windinguof relay k36,v conductor 92, contact 93 of cut olf key 55, conductor 94, contact 95 of cut oi key 55, conductors conductor mute i completes an energizing circuit for therelays 35and 36. lThe operation of relay 35 closes its contact 100 and completes a bridge of the cord conductors including the Winding 2O of the coil 21. This circuit maybe traced from the middle point 101 of the Winding 10, conductors 102 and 103, condenser 19, 104, winding 20, conductor 105, vcontact 100 ofrelay 35, conductor 106, contacts and 81 of relay 31, conductor 107, conductor 108 and conductor 109 tol the middle point 110 of winding 11. Thisconstitutes the input circuit of the repeater and as will be noted, can'o-nly be completedwhen the plugs are in their jacks, thus preventing the repeater from humming in case one of the plugs is accidentally pulled down. This feature is further guarded against by having the coils 10 and 11 normally shortcircuited through normally-closed contacts 114 and 115 of the relay 36, which are openedwhen this relay operates.

In the operation of the repeater, voice cuI-, rents coming over the line to the end of the plug 5 will find a path over the conductors 7 and 8, through normally closed contacts 116 of a ringing key 117, normally closed contacts 118 of the cutoff key 55 conductors 119, 120 through one set of windings 50, 51, conductors 121 and 122, conductors 123 and 124, the two left-hand halves of the wind, ings 10 and 11, and the bridgeof the coil 20 previously traced. vThis will-induce currents in the winding 22 of the coil 21, which induced currents Will cause the movable polepieceof the repeater to vibrate. The vibrations of the movable polepiece and its attached electrode being made more forcelful by the initial magnetization produced by current in winding 18.. Assuming that the pole changing relay 23 is in the position shown, the circuit-s for the induced currents will be from one side of the winding 22 over conductor 125, contact 126 of relay 23, conductor 127, conductor 128, conductor 88, winding 17, conductor 129, contact 130 of relay 23 and condenser 131 to .the other side of the lwinding 22. The reciprocation of the plunger caused by the current in this last traced circuit will cause an 'agitation of the comminuted material between the electrodes of the transmitter 16 and a consequent variation in the resistance of the circuit and the battery current through the winding 12 which will in turninduce a current in the other halves of the windings 10 and 11, conductors 132 and 133, the other 'set of windings 50 and 51, conductors 134 and 135 normally closed contacts 136 of Cutoff key. 55, normally closed contacts 137 and tothe line withA which `ductor 157 to the of ringing key 11'7jto cohduct-ors 7 and 8,

plug (i is connected. The circuit'under consideration being a two-way repeater circuit, it is clear that in talking from the end of the plug 6 the paths for the incoming and outgoing voice currents wou'ldjfbe just the reverse of those traced.'

Referring now more specifically to the su -pervisory features of the system, it will be noted that when the key 54 is operated, it connects the receiver 53 and Winding 52 in'series, the circuit being as follows: from one side of winding 52, conductor 150, contact 151 of. key 54, conductor 152, conductor 153, receiver 53, conductor 154, conductor 155,l contact 156 of key 54, and conother-side of the winding 52. This places the receiver 53 in condition to receive induced currents from the kWindings,'50, 50 and 51, 51 and any difference in phase of the currents on opposite sides of the repeater due to difference, in the impedance upon the two sides of the repeater bridge will be indicated by blurred receiving, which results with the receiver in inductive relation to the line uponboth sides.

'of the repeater bridge, the true condition of the circuit upon both sides of'the repeater bridge will be indicatedto the'operator and the three requirements previously set forth will be met. l

The control of the repeater to compensate for certain variables met with such as fluctuating battery voltage due to charge and discharge, and high resistance transmitter elements of the repeater due to continued use may be governed by regulating the output of the repeater and changing the phase relation of the input and output currents of the repeater to compensate for unbalanced conditions of the line.. This may be accomplished in various ways, such for instance as reversing the terminals` of the primary Winding 12 in the output circuit, reversing the terminals of the input winding 20 or reversing the terminals of the operating winding 17 of the repeater. This last is the preferable method and the one shown on the drawing. To explain more fully, it is to be noted that the repeater is a polarized instrument and of the transmitter plunger will therefore be dependent upon the polarity of the repeater operating current. There is naturally a slight lag in the transmitter element, due to the inertia of the parts, and it may well happen, and frequently does in practice, that due to the polarity of the operating current and the inertia of the movable parts, the repeater current is approximately behind the operating current, under which condition-a condition of imbalance between the line and the repeater circuit results, andthe the direction of movement Y opposing or canceling,

noted that the yadvance of the slide thus increasing the current and re 167, contact 165 of key the middle point of currents in these two each other. The-reversal offthe polarity of the repeater .will change the of the repeater' current of the operating current. so that instead of these currents will be in 'a proper phase with respect to each other t'o produce the 4best conditions for talking.

Referring first to the ing the output of the receiver,

means for regulatit will be member 42 into engagement with thel last three of the sets of springs 40, 40 short circuits the resistance elements 43, 43 in'series with the battery 34 and the transmitter element 16 and magnetizing coil 18 lating the output of the repeater. The ot er lfeature of the adjustment, namely that of changing the phase relation of the output and input currents of the repeater to the unbalanced condition of the line, is accomplished by the actuation of the set of .contacts 41 by.

depressing the slide member into the vposition indicated in dotted lines on the drawing and moving it into engagement with the said contacts. The closure of the contacts 41 completes a path for current which may be traced as follows: from battery 34, con' tacts 82 and 83 of relay 33, `conductor 84,

contact 41, conductor 160, and a' winding of relay 23 to ground. Current inl this path operates the relay 23 opening itsjback contacts 126 and 130 and closing its front contacts 161 and 162 thus reversing the poling of the operating winding 17. The slide keyl is so arranged that the plunger member 42 cannot be depressed in any except its'normal position, or when it is entirely .free from engagement with the contact springs, thus making it impossible to change the poling .of the receiving element with the full battery current through the output circuit.

When the talk and listen key 62 is operated, it breaks ground contact and closes contacts 165 165 and connectsthe secondary 61 of the induction coil across the line at the middle points of the windings lOvand 11 with the receiver in series with one of the windings and in parallel with the other.` The bridge will be as follows: 'from the middle point 110 of winding 11, conductor 109, conductor A62, ,conductor 168, secondary winding 61, windin 169 and 170 conductor 171, normally close contact 17 2 'of monitoring key 54, conductor 1 55,.condenser 173, conductor 174, theotber' contact 165 of key62, conductor 175, conductor 176 and yconductor 102 tothe middle point 101 of winding 10.- The receiver 53 is connected with the winding 61 and one 173. The breaking of the circuit :for reside of the condenser the ground contact opens divisions will cancel phase relation to c o-act with that,

of the repeater 15,l

.17 of the'` re lays 35 and 36, thus rendering rthe repeater inoperative. c

In the operation of the supervising relay 26, ringing current coming from either end of the line, will come in over one side of the line to the middle point .101 of winding 10, through conductor 102, conductor 176, conductor 180, winding of relay 26, condenser 25, retardation coil ,24, conductor 108. conductor 109 \to the middle point 110 of winding 11 and back over the other side of the line. Current in this path will energize relay 26, causing it to operate and close its contact 181, the relay 27, which may be tracedA from bata tery, 34 through the Winding of the relay '27,' conductor 182, contact 181 of relay 26,

conductor 183, conductor 184, conductor 97 'and contact 98 ofthe talk and listen key to ground. Current in this circuit operates the relay 27 to close its contacts 185 and 186,

i which closes a circuit for the relay winding and supervisory lamp which is the same as that just traced, except that conductor 187 thus completing a circuit forv is substituted for the path through the contact 181 of relay 26. vCurrent in this lastnained circuit retains the relay 27 in its operated position, and the supervisory lamp 28 lighted untilthe talk and listen key 62 is operated. The combinedjimpedance of the retardation coil 24, condenser 25 and relay 26 is suchA that the circuit including them will afford a ready path for the ringing currents, :but will not appreciably sunt-the talking' currents; The-operation of theringing key 117 short circuits the operating coil eater, this short circuit being rough contact y190 in one' posiestablished vt 1. 'In a telephone repeating the of a reto said currentinducing with said ypeater circuit bridged between said conductors, a pair of current inducing windings connected in each of said conductors oneon yeach side of said repeater circuit,-a secondary winding in inductive relation to said current inducing windings,

means for connecting said receiver in circuit with sa-id secondary kwinding.

3-."In a telephone repeating system vthe combination with link conductors, of, switch- .tion ofthe ringing key, and through contact i 191 in the other position of saidkey.

a secondary winding in ina receiver and ing means for connecting ltheopposite ends of said conductors Awith .line wires, la vreunder thejoint ing means for completing sald repeater cir` i peater circuit adapted to be bridged -between said link conductors, and switchin'gmeans control of the link connectof said conductors with line wlres, a tele.

phone, repeater, a circuit'for said repeater, electromagnetically controlled switching means for bridging tween said link conductors, a switching key,

.and a sourcev of current the connection of which. with said electromagnetic switching means andl said repeater is under the joint control of said switching means and said link connecting means.

5; In a telephone repeating system the combination with link conductors of switching means for connecting the opposite ends of said conductorsv with line wires, a repeater circuit, relays for connecting said repeater circuit in bridge of the link conducto-rs, the operation of one of said relays being under the control of one of said link connecting means and the operation vof the other of said relays other of said link connecting means.

In a telephone repeating system the combination .with link conductors, of switching means for connecting the opposite ends of said lconductors with line wires, a repeater, secondary windings in said link con'- ductors adapted to receive induced currents resulting from the operation of said repeater, a relay, and contacts controlled by said relay normally short circuiting said secondary windings, the operation of said relay being under control of one of said link connecting means.

7. In a telephone repeating system the combination with link conductors, of switching means for connecting said conductors with lline wires, a repeater, input and output circuits for said repeater, and electromagnetic switching means operated in the making and unmaking of connections of said link conductors with the lines to control the association of said input and output circuits with said link conductors.

8. In a telephone repeating-system the combination with a three-wire connecting circuit comprising tip, ring and sleeve conductors, of connecting means associated with each end of said connecting circuit, a relay in each of the sleeve wires operated in the making and unmaking of connections with the corresponding connecting means, a repeater, an input circuit for said repeater adapted to be bridged between the tip and ring conductors of said kconnecting circuit. said bridge being controlled by both said sleeve relays, and-an output circuit for said said repeater circuit be-v 'elated for changing the phase relation of the input 8.0

being controlled by thel `duction coil primary lays.

9. In .a telephone repeating system the combination with link conductors,'of a telephone repeater having an input winding inductively related to said link conductors, an

'energizing .ci-rcuit Vfor said repeater, and ivmeans for controlling the poling'of said ingput winding and'means for controlling'the amount of energy in said energizing circuit. 10. In a telephone repeater combination with telephone lines, of link conductors for connecting said telephone lines, a telephone repeater operatively assowith said link conductors, and means and output currents of said repeater to com- 1pensate for unbalanced conditions of said ine.

1l. In a telephone repeating system the combination with link conductors, of a telephone repeater, input and output circuits for said repeater operatively related to said link conductors, and means for reversing the polarity of current in one of these circuits with respect to' the currents in the other of 90 said clrcuits. f

12. In a telephone repeating system the combination with link conductors, of a telephone repeater having an operating winding inductively related to said link conductors and means for reversing the polarity of current through said operating winding.

13. In a telephone repeating system the combination with link conductors, of a telephone repeater, an operating winding therefor, an induction coil secondary winding in circuit with said operating winding, the primary winding of said coil being connected in bridge of said conductors, a pole chang ing switch in said secondary circuit and 10 5 means for operating said switch. i

14. In a telephone repeating system the combination with link conductors, of an inpole changing bridged between said conductors, a telephone repeater, an operating winding therefor, a secondary winding for said induction coil in circuit with said operating winding, pole changing lay for controlling said contacts and a manually operated switch for controlling the circuit of said relay. l

15. In a telep-hone repeater system the combination with link conductors, of a tele- 120 having an operating windrelation to said conductors, operating repeater,

phone repeater ing in inductive a pole changing relay for said winding, anoutput circuit for said a source of energy therefor and for changing relay, and a two position key adapted in both positions to vary the en ergy of the output circuit and in one posltion repeater controlled by one of said sleeve re- 65 system the 75 winding adapted to be contacts in said circuit, a resaid pole only to control the circuitof the lpole changsecondaryl'wiiidings inshunt with said re- 10 L y e inge` relay. peater bridge. y

16. In a telephone repeater system the Inwitness whereof, I hereunto'subscribe combinaon wih link coiductors, 0i ingucmy name. f

tion coi secon ary win ings connecte in l s said conductors, a telephone repeater circuit EERBERT E' SIBEEYE' in bridge` of said conductors at the middle Witnesses: points of said secondary windings and a su- WALTER F. HOFFMAN,

pervisory relay connected vin vbridge of said IRVING MACDONALD. 

